Biomedical subjects
Publications and source records attributed to S Hayasaka.
A Japanese infant was found to have abdominal distension at the age of 4 weeks. A diagnosis of galactosemia was made at 8 weeks of age. Dietary management completely reversed the hepatosplenomegaly and ceased the progression of lens opacities. Mental retardation was also noted at a later age. We believe this is the first reported case of galactose cataract in Japan confirmed enzymatically.
Regional distribution of lysosomal enzymes in the retina and choroid of human eyes was studied biochemically. Specific activities of acid phosphatase, cathepsin D, and arylsulfatase in the retina and choroid varied by area were also studied. The macular area showed the highest activities in comparison to other areas.
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Three cases of Japanese patients with gyrate atrophy of the choroid and retina with hyperornithinaemia were studied clinically and biochemically. The types of disease differed in responsiveness to vitamin B6. In-vivo responsiveness to vitamin B6 was correlated with in-vitro data. It is suggested that the in-vitro examination of the influence of pyridoxal phosphate on ornithine ketoacid transaminase activity in cultured fibroblasts may be useful in ascertaining the efficacy of vitamin B6 treatment in gyrate atrophy. In addition the early development of the fundus lesions was observed in one case (case 1), and the ciliary body abnormality and chorioretinal atrophy were noted in another (case 3).
A 44-year-old woman with atypical gyrate atrophy and iminoglycinuria was described. The serum ornithine level and ornithine-ketoacid transaminase (OKT) activity were both normal. Urinary excretion of proline, hydroxyproline and glycine was markedly increased. This finding, together with the existence of gyrate atrophy with hyperornithinemia due to OKT deficiency, suggests that proline deficiency in the chorioretinal tissues may concern the development of gyrate atrophy.
Two patients with hyperornithinemia and gyrate atrophy of the choroid and retina, the first report in Japan, were described. Serum ornithine was increased 10- to 15-fold and serum lysine was slightly decreased in the affected patients. Urinary excretion of ornithine was also markedly increased. There was no increase in serum proline after the oral loading of ornithine in the patients, whereas serum proline increased after the loading in normal controls. Ornithine-ketoacid transaminase (OKT) activity was markedly reduced in phytohemagglutinin transformed lymphocytes from the patients. In all of their parents and one of the siblings, OKT activity was found to be decreased to about half of the normal control values. These findings indicate that the pathway from ornithine to proline is a major route of ornithine catabolism in man. A possible pathogenesis of ocular disturbance in the patients with OKT deficiency was postulated.
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Hyaluronidase activity in human corneoscleral tissues was biochemically studied. The corneoscleral junction, particularly the inner layer, showed higher activity than other corneoscleral tissues. The possible role of lysosomal hyaluronidase in the trabecular meshwork is discussed.
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Ornithine ketoacid aminotransferase in bovine ocular tissues was studied biochemically. The retinal pigment epithelium, ciliary body, iris, and neuroretina showed high specific activity. The cornea and choroid revealed a lower activity. Aqueous humor, lens, vitreous body, and sclera showed no activity. The pH optima of the enzyme in the retinal pigment epithelium and ciliary body were near 8.0.
Cathepsin B and collagenolytic cathepsin activities were studied biochemically in human aqueous humor. The enzyme activities were found to be significantly high in the aqueous humor of the patients with Behçet's disease, but not detectable in those with senile cataract, retinoblastoma, and maxillar carcinoma. These data suggest that cathepsin B and collagenolytic cathepsin have a certain role in the inflammatory collagenolytic process of Behçet's disease.
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